Why do CT scanners need to spin so fast?
In: Engineering
A CT scanner takes x-rays from all angles and composits them into a single 3D image. The faster it spins, the quicker it can move around to take those x-rays and complete its work. Apart from improving the machine’s time efficiency and making it overall a more convenient thing to operate, the higher speed also helps it generate more accurate scans. Think of the spin rate like the shutter speed of a camera. The slower the shutter, the longer it stays open to let light in, which creates blurry images from all the movement. There’s less movement (of the subject patient) between each “snapshot” of a faster CT scanner, so each image is clearer and the end result is higher quality.
They don’t. But the speed they can make the image, and hence how quickly they can get results, how many machines you need to buy for a particular patient load, how much each CT scan costs, etc. all scale with how fast it spins.
A faster spinning machine is more productive, more efficient, and produces results faster (can be important for some conditions).
It’s like asking “why do cars need to go so fast?” They don’t, but we’re all happier with faster cars up to the point that safety starts to get compromised.
You can tell people “stay still”, but that doesn’t keep them from moving, they keep breathing, their hearts keep beating, and all that sort of stuff. If you take measurements slowly, there will be more motion between measurements. In the long run, you won’t be able to compensate for all of it, and the results will be less accurate. The faster you go, the less time for movement, and thus the less movement and the better the measurement data.
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